Thermomechanical Properties of β‐Sialon Synthesized from Kaolin

β‐Sialon powder was synthesized by the simultaneous reduction and nitridation of Hadong kaolin at 1350°C in an N 2 –H 2 atmosphere, using graphite as a reducing agent. The average particle size of β‐sialon powder was about 4.5 μm. The synthesized β‐sialon powder was pressureless sintered from 1450° to 1850°C under a N 2 atmosphere. The relative density, modulus of rupture, fracture toughness, and microhardness of β‐sialon ceramics sintered at 1800°C for 1 h were 92%, 248 MPa, 2.8 MN/m 3/2 , and 13.3 GN/m 2 , respectively. The critical temperature difference (ΔT c ) in water‐quench thermal‐shock behavior was about 375°C for the synthesized β‐sialon ceramics.